How They Run Morgan Falls Dam

A few weeks ago I got a little frustrated with the unpredictability of the generation schedule at Morgan Falls Dam on the Chattahoochee. For those of you unfamiliar, Morgan Falls is a very small dam which was built in 1904-05 for purposes of providing the Atlanta streetcar system with power. Today it is owned and administered by Georgia Power, a division of the Southern Company. In this it is unlike Buford Dam, which holds back Lake Lanier further upstream. Buford Dam is an Army Corps of Engineers Dam and is administered by the Corps. (One other regional player when it comes to dam administration is the TVA, which runs several dams in North Georgia as well as, of course, in Tennessee).

My frustration reached a head when I called the Morgan Falls Dam hotline, 404-329-1455, which the National Parks Service references as having a “water release schedule.” In calling the Dam hotline I realized that this was not the case; instead river users are treated to about a three minute legal disclaimer followed by (on the day I called) a second recording stating that the Dam might release anywhere from 0 to 15,000 cfs, you know, some time in the next twenty four hours.

I wrote the Georgia General Assembly and Senate delegations from Sandy Springs, which is the home district of Morgan Falls Dam, a letter expressing my belief that this “water release schedule” is at best lackadaisical and at worst potentially dangerous. After all, people die on the river every year, at least in part because they underestimate or are not aware of the river’s changing flows.

To my utter surprise our state lawmakers pulled through and got me set up with Herbie Johnson, an extremely nice administrator for Georgia Power/Southern Company. Herbie arranged a tour and personally guided me, as well as board member and fellow lawyer Scott Kitchens, on a tour of Morgan Falls. We met the entire dam staff including the hydrologist responsible for the dam’s generation schedule. The tour was eye opening.

Purpose Statement

The first thing you have to understand about Morgan Falls Dam is that it was never built for purposes of flood control at all. In fact, by percentage, Morgan Falls holds back approximately .2% of the total water behind Buford Dam. You read that right: two tenths of a percent. Specifically Morgan Falls currently retains 2,250 acre feet of water (a volume measurement based on recent studies which do include the siltation the lake has suffered), whereas Buford Dam holds back 1,089,400 acre feet. In terms of capacity, Buford Dam has enough water to run continuously for 259 days before it would hit the bottom of the lake. Morgan Falls Dam can run for… half a day.

This handout from our meeting is TO SCALE!

Siltation is another area that was of great interest to me. The perception in the fishing community is that all the siltation behind the lake happened in the 1990s when Atlanta exploded. It turns out this is not the case. Bull Sluice Lake has largely been at hydrological equilibrium since the 1950s. Today new silt deposits are primarily washed down stream. The lake will never totally “fill in” due to the effects of this equilibrium.

The problem with a lake having only 1/2 day’s worth of capacity is exacerbated by Morgan Falls’ distance from Lake Lanier. No matter how much water Buford Dam generates, it takes at least 12 hours for that pulse to reach Morgan Falls.

Contract Issues

Morgan Falls Dam is operated subject to a contract with the Atlanta Regional Commission. This is a public water use cooperation board which is in charge of regulating not just how much water Buford and Morgan Falls release into the Chattahoochee, but also how much is subsequently drained by entities like the Cobb-Marietta Water Authority. In order to regulate this amount of water flow and make sure that there is always water for the downstream stakeholder entities to suck out of the river, the ARC requires Georgia Power, via Morgan Falls, to hit a 750 cfs minimum flow as measured at Peachtree Creek.

Remember how Buford Dam is operated by the Corps of Engineers? That is not a division of Georgia Power, needless to say. Moreover, the two entities have surprisingly little interaction. Last year there were two instances where Bull Sluice Lake ran almost completely dry. It turns out these instances were caused by staffers at Buford Dam (the Corps’ Dam) changing their mind about (or failing to follow) the predicted schedule they had released the day before.

Morgan Falls’ dam operator literally sits in a soundproofed control room in the turbine area inside the Dam. When we were there, that operator had printouts of emailed copies of Buford Dam’s predicted schedule on his desk. This is how Morgan Falls knows when to expect water! Because of the 12 hour time lag between Buford and Morgan Falls, the operator at Morgan Falls (who is a really nice guy incidentally) is forced to guesstimate how much water he will be receiving from Buford Dam as well as how much he needs to release to hit his 750cfs minimum flow at Peachtree Creek.

On the two “dry out” days last year, Buford failed to send water as scheduled, but Morgan Falls still was obligated by its contract to feed the lower river. If they did not, the intake pipes could have run dry for much of Metro Atlanta’s water needs, which in turn could cause sanitation issues in the water you and I drink. The result of Buford’s failure to follow its own schedule was a dry lake, a Georgia Environmental Protection Division investigation and–surprisingly–a visit from the Corps staffers to Morgan Falls for the very first time. Staff at Morgan Falls reported a much better working relationship with the Corps staff once the Corps employees saw with their own eyes just how little Morgan Falls staffers had to work with.

A Balancing Act

The impression I came away with was that Morgan Falls staff has to run a very delicate balancing act to meet their requirements with little more information than we as fishermen have about what Buford Dam will be doing. Without water from Buford, Morgan Falls (and Bull Sluice Lake) both go dry. Meanwhile Buford Dam is operated for flood control purposes and due to the massive volume differential between it and Morgan Falls, Buford can easily overwhelm its downstream sibling with too much water. Finally, Buford is operated at a considerable profit by the Corps pursuant to its relationship with SEPA, the Southeastern Power Administration. Buford Dam runs its generators when power is needed (hydropower being AC as opposed to DC, it cannot be stored and must be generated on demand). Power is typically at highest demand (and highest profitability margin) in the mid afternoons. That leaves water reaching Morgan Falls twelve hours later in the middle of the night. Morgan Falls subsequently generates and passes the water downstream. This hand-to-hand act results in a “reregulation effect” whereby Morgan Falls smooths out the crests and troughs of Buford’s generation. At the same time, it means when Buford releases a slug of water, Morgan Falls has only twelve hours to guesstimate the amount of downstream flow–and that guesstimate can be overwhelmed by other factors like a quick rain event. The end result is a very unpredictable generation schedule primarily due to Morgan Falls’ inability to retain much water. Instead, it essentially passes through whatever Buford releases.

Well, Let’s Dredge Then

Just make the lake deeper then, right? Not so fast. In 2007 Georgia Power did a study to determine what benefit could be gained by dredging out some additional upstream capacity and thereby deepening Bull Sluice Lake. Bad news: the total cost was $140M. More bad news: dredging the lake only bought Morgan Falls another 1/4 day of total capacity. In other words, all that cost would have had no effect on how Morgan Falls is operated today. And remember, the lake is already at hydrological equilibrium. Deepen it and you will simply have to do it again in another three or four decades. Moreover, the silt itself is widely expected to be toxic, although the operators we met with admitted that the toxicity tests have not yet been performed.

Well, what about Dam removal then? This is where it gets interesting. Mr. Johnson speculated that if Georgia Power owned Buford Dam and also owned the downstream impoundments detaining West Point and other Chattahoochee lakes, then it might make sense to remove Morgan Falls. It would certainly alleviate many of Georgia Power’s customer complaints about how it runs the Chattahoochee. If there were no Morgan Falls, then Buford’s slugs of water would dissipate naturally as they ran through the river system. Of course, this would also transport all the silt downstream and be even more expensive than dredging.

Morgan Falls is not, in fact, as decrepit as it appears. The amount of scaling seen in the concrete on the downstream side is considered excellent given the Dam’s 110 year age, and also is largely cosmetic in nature. Mr. Johnson indicated that when the winter ice freeze (the usual cause) has chipped enough of the concrete away to expose rebar, then the dam will be re-faced. Meanwhile, there is no pressing need to do any concrete work on the dam. We actually had the opportunity to stick our heads in a turbine chamber which was dried out for repair. Although completely eerie and somewhat terrifying, the inside of the Dam is in excellent condition.

So We Just Deal With This Then?

Not exactly. Georgia Power is clearly sensitive to river users’ concerns. They also expressed understanding of the potential legal liabilities involved in running the dam (although they pointed to the considerable insulation they are afforded by the Georgia Recreational Use Statute, which essentially states that river users assume the risk of injury as a matter of law). They were very proactive in responding to our complaints and offered the Dam tour unsuggested so as to explain their process. They also indicated that they are looking into revising their phone disclaimer and providing a more updated online schedule, partly as a result of our meeting. (Indeed, at the meeting the hydrologist admitted she had not known the Parks Service was referring river users to the phone number at all).

So, the good news is Georgia Power is obviously willing to work with the river using community. Mr. Johnson specifically requested that we inform others that the Dam is open for tours and they are more than happy to show anyone how they operate. I was very impressed with Georgia Power’s transparency and I came away hopeful that, partly as a result of the two lake dry-out incidents last year, Georgia Power and the Army Corps will be in better communication in the future, which, in turn, should allow Georgia Power to make good on its intention to improve the online and phone schedule.

I'm the owner and editor of The Itinerant Angler and the host of the podcast. I'm also a national print magazine writer and photographer, providing content to a wide variety of publications. For more information, please check out the About page. If you need to contact me, please email me at ZachMatthews@gmail.com.

8 Responses to "How They Run Morgan Falls Dam"

– They keep the generator rotors spinning basically all of the time, in some cases the generators are hooked up to the turbines (when they are generating) and the rest of the time, they actually consume power spinning the generators. Spinning them when not generating provides two benefits (1) voltage stabilization to the grid – think of them as big flywheels that can both give and take from the grid, exactly like a capacitor and (2) allows, if needed, a nearly “instant on” generation ability if there is an outage elsewhere in GP’s generation network.

– The crappy looking, crumbling facade was added in the 50’s and is non-structural.

– Most of the power is used locally in Roswell / sandy springs. The local plant manager pointed to two sets of very small looking wooden-pole type power lines and said that is where the power goes.

– If the water is up and a few spillway gates are open, they can’t generate power effectively at this plant because the difference between the tailrace water level and the spillway level has been significantly reduced.

– The GP people do want to figure out how to publish something online as far as a schedule, but the lead time would not be much since the storage capacity is so limited.

– Think of Morgan falls as between a rock and a hard place.

– The Rock: they are obligated to deliver 750 CFS to the Hooch at Peachtree Creek / Atlanta Wastewater plant PLUS MF has no ability to store any appreciable amount of water to help it meet this requirement.

– The Hard Place: Buford dam’s low flow is about 600CFS (which is most of the time) and its generating flow is up to 10,000CFS.

– Result, MF’s generation schedule has inherent unpredictability to it. Their discharge is wholly dependent on Buford dam and inflows from rain events, which due to low storage they cannot buffer very well. Instead, most of what comes in in the form of 10,000 CFS pulses from Buford must go out immediately. Plus they have to draw-down MF to make sure there is space when the 10,000 CFS hits.

Fascinating article on what has been a mystery to me in fishing the river for 30 years now. I have to respectfully question the dredging/extra storage capacity part of the article though. As someone who has float tubed and been in a friend’s bass boat right up to the lake side of the dam, it is scary how shallow that thing is. The pictures from the dry lake events show even more. Also, in the early days of my fishing career, you could fish the lower river almost anytime they were releasing water-except for big releases and after heavy rains and the water stayed relatively clear. Now the river gets cloudy and stained at the slightest rise in water level and sadly the thermal pollution of summer has doomed our finned friends most years. Thanks again for a great article..

I think the pollution issues, Michael, are less to do with the Dam itself and more to do with point-source runoff from all the subdivisions which have been built in the north Fulton area in the last thirty years. I’ve floated from Buford Dam down after rain events and you can literally see lines in the river where this or that homeowner has mud running off into the water. That is a matter of enforcement, specifically of NPDES regulations for point source pollution, and should be reported to the Georgia EPD using this phone number: 404-675-6240.

Zach, I agree -the dam itself just keeps the silt and pollution here and doesn’t allow it to naturally head downstream. I also have seen these lines of mud flowing into the river over the years especially in the heyday of North Metro development.
I guess it’s inevitable with an artificial trout fishery and our fine particle clay soil to have this silt problem.

What a great website you have! It’s gonna be on my morning coffee surf list..

Thanks for your article. I recently happened upon the Damnation documentary and was interested to know how dams were effecting our waterways in North Fulton. I admit to knowing very little at this point. I enjoyed reading such a well researched and clearly written explanation. It was very interesting to hear the current condition of Buford Dam and to know its productivity. I’d like to know more about how the dams in our area effect wildlife. The GADNR websites suggest they provide necessary wetlands that have been a boon to native wildlife, although it also mentioned stocking the river with hatchery fish.

Awesome information and so glad you shared. Is there anything that you have learned or that has changed in the past 24 months since writing this that might help better know river flows south of Morgan Falls? I recently bought a jet drive boat and plan to do a lot of fishing this summer! Based on what you have told me, it sounds like Morgan Falls will mimic Buford Damn to a lesser degree. So my first step is to look at Buford Damn release schedules and then to look up the water flow charts below Morgan Falls Damn http://waterdata.usgs.gov/nwis/uv?site_no=02335815 and see where they are trending. If I use a 12-14 hour window from the Buford Damn releases, than I can tell if a water release will likely be coming/headed…..but it sounds like the guy in the soundproof room might still have to not fall asleep and his 12 hour old e-mail print out has to still be correct! Let me know if you think there is a better way to try and predict water flow south if you don’t mind. Thanks!